They’re neat (I’ve only tried Uni’s), though imho I prefer the manual control of a regular mech/pencil when writing in cursive, because then I can choose when to rotate the lead (ie by rotating the entire pencils).
If you’re used to writing with pencils you don’t even think about it anymore. It’s as natural as dotting an i
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Can’t say personally, but for many it’s the first time they’re even looking at what other engines have to offer.